Memory Upgrade Frequently Asked Questions (FAQ) - Technical Questions and Answers

The CompuRAM product portfolio ranges from memory upgrades for workstations, mainboards, servers, PCs, printers and notebooks to modules according to industry standards.

CompuRAM provides about 4.000 memory components for all computer systems of well-known manufacturers, as well as solutions for special and old devices.

Due to our sole specialisation on memory upgrades and our long term experience and best contacts to memory and system manufacturers we can offer our customers high-quality and absolutely compatible products to very reasonable conditions and in as short as possible delivery times.

Basically, for the usage of more than 4GB memory a 64-bit operating system is neccessary.
Due to PC architectural requirements such as motherboard resources and OS limitations, platforms using larger memory may be unable to take full advantage of all memory populated on the system.

When systems with chipsets, that support 4GB or more of system memory, are populated with 4GB or more, the Operating System (OS) may report a lower amount of available memory. Standard PC Architecture System Resources require addressing which overlaps physical memory below 4GB:

• System BIOS
• Motherboard Resources (I/OxAPIC)
• Memory Mapped I/O
• PCI Express Configuration Space
• Additional PCI Device Memory (Graphics Aperture)
• VGA Memory
• Others as included, etc..

These requirements may reduce the addressable memory space available to and reported by the Operating System. These memory ranges, while unavailable to the OS, are still being utilized by subsystems such as I/O, PCI Express and Integrated Graphics and are critical to the proper functioning of the PC.

x86 chipsets that support more than 4 GB of RAM typically also support memory remapping (referred to in some BIOS setup screens as "memory hole remapping").
In this scheme, the BIOS detects the memory address conflict and in effect relocates the interfering RAM so that it may be addressed by the processor at a new physical address that does not conflict with MMIO.
On the Intel side, this support once was limited to server chipsets; however, newer desktop chipsets like the Intel 955X and 965 and later support it as well. On the AMD side, the AMD K8 and later processors built-in memory controller supported it from the beginning.

Please find detailed explanations about this topic from the view of Microsoft here:

http://support.microsoft.com/kb/929605/de

It is absolutely neccessary for a properly running system to always have the latest BIOS version installed. In general, all system manufacturers offer the latest BIOS versions for downloading on their websites. (Please also read your manual for more information.)

Because the control functions in the BIOS also contain parameters as e.g. timing and memory (RAM)- settings, it is important to make sure that the latest BIOS version is installed when installing additional memory.

Thus a BIOS-update is the first solution when problems occur with new or additional components. This is also applicable for original memory modules as well as for our CompuRAM upgrades.

You can use the Windows Memory Diagnostic Tool by Microsoft to test if the memory, independent from the particularly installed operating system, has been integrated properly into the system by the BIOS:

• When errors occur during the tests, the first step is to make sure that the memory has been integrated by the BIOS into the system at all.
  
• When no errors occur during the tests, that means the memory is being tested as O.K., the error can be assumed to lie in the installation/configuration of the operating system.

You may download the Windows Memory Diagnostic Tool and the correspondent instructions directly from the Microsoft homepage:

http://windows.microsoft.com/en-gb/windows7/diagnosing-memory-problems-on-your-computer

For Windows:

Manual for computers with Windows operating system

For Apple:

• With the serial number of your Apple you can access your model data here.
  http://support.apple.com/specs/
• If you are using MAC OS X you may read out the exact system data with the System Profiler.
  System Profiler -> "About this Mac" -> "More information"

Basically you can rely on the fact that all upgrades we matched to certain system models are compatible and mixable. If system upgrades are subject to special specifications we will mention it seperately.

The best option is to buy the upgrade with the highest clock speed, especially because prices often differ slightly.
For example 400MHz instead of 333MHz or 1333MHz instead of 1066MHz etc.

Our clock speed indication always refers to the memory modules MAXIMUM possible operation modes.

Despite the still common opinion, DIMM or SO-DIMM do not have an own clock speed but are alwaysbeing clocked by the system bus..

The maximum, but especially the minimum, memory clock speed is predefined by the memory s possibilities, the chipset, the CPU and often the systems manufacturer. The clock speed justifies itself during the booting process by BIOS routines to maximum possible and secure values.

Conclusion:

• The slowest memory module always determines the clock speed for all RAM installed in the system.
• Thus you can mix different "fast" modules carelessly, if we offer them.
• Your system is justifying itself during the booting process to ideal, stable and secure values.
• he indication on the modules resp. in the article description refers to the maximum timing values. These values are standardised according to JEDEC and INTEL worldwide.For these standards a different wording is being used. For example: The indications DDR400, PC3200 or 400MHz are basically all the same specifications.
• For our upgrades, we always use the most current and fastest DRAMs and never old items. That means, that we are tendentially provide upgrades that allow an even higher timing than neccessary for your system.
  
  

Basically, for the usage of 4GB or more memory a 64-bit operating system is neccessary. Here you find an overview of maximum memory of the MS Windows operating systems